The present invention generally relates to failover for servers.
A cold standby system such as that described below, for example, is known as a server failover system. More specifically, a plurality of servers are connected in an accessible fashion to the same storage apparatus, and a spare server (replacement server) is prepared in respect of the current server (operating server) of the plurality of servers. If a fault occurs in the current server and it becomes impossible to continue processing, then the spare server is started up and the OS, application, or the like, running on the current server is loaded from a particular storage area inside the storage apparatus (for example, from the system volume which is the logical volume where the OS (Operating System) or application, or the like, is stored). By this means, the processing is taken over from the current server to the spare server, and the spare server can operate as the current server.
The storage apparatus which can be accessed from the plurality of servers is provided with security measures in order to prevent mistaken access to a particular storage area (for example, a logical volume) by a server that is not originally supposed to perform access. If connections are made by fiber channel, then access rights are controlled by using an identifier such as a World Wide Name (WWN) which is assigned to the host bus adapter (HBA) mounted on the server side. In order for the spare server to be able to use directly the storage area being used by the current server, it is necessary for the access rights to be passed on (taken over) appropriately in the event of a failover. The first and second technologies described below are technologies for passing on access rights.
A first technology is a method which exchanges the WWN of the HBA mounted on the server. According to this method, in the event of failover, the WWN is changed between the HBA mounted on the current server and the HBA mounted on the spare server. This method is disclosed in Japanese Patent Application Publication No. 2007-164305.
A second technology is a method which uses an I/O (Input/Output) switch. The I/O switch is provided between the server and an I/O device (for example, a HBA or NIC (Network Interface Card)). If a fault has occurred in the current server, then the I/O device used by the current server is allocated to the spare server by changing the settings of the I/O switch. By this means, the spare server is able to take over the storage area inside the storage apparatus which was accessed by the current server via the I/O device. This method is disclosed in Japanese Patent Application Publication No. 2007-280237, for instance.